[Notifications] Make image background white like notification background

ui/message_center/message_center_style.h

Index: ui/message_center/message_center_style.h
diff --git a/ui/message_center/message_center_style.h b/ui/message_center/message_center_style.h
index 128d444d560ebb815215b2b2ae89e2eacdec79e2..9d72789bba4a8c0254c339e7fda42c84baa7da0f 100644
--- a/ui/message_center/message_center_style.h
+++ b/ui/message_center/message_center_style.h
@@ -80,7 +80,7 @@ const int kMessageLineHeight = 18;         // In DIPs.
 // Background of the card.
 const SkColor kNotificationBackgroundColor = SK_ColorWHITE;
 // Background of the image.
-const SkColor kImageBackgroundColor = SkColorSetRGB(0x22, 0x22, 0x22);
+const SkColor kImageBackgroundColor = kNotificationBackgroundColor;
 // Title, message, ...
 const SkColor kRegularTextColor = SkColorSetRGB(0x33, 0x33, 0x33);
 const SkColor kDimTextColor = SkColorSetRGB(0x7f, 0x7f, 0x7f);